Among current patients with visual deterioration, some patients choose to implant a retinal implant to improve vision. At present, the only retinal implant approved by the U.S. Food and Drug Administration (FDA) has only 60 pixels and is expensive; therefore, the improvement to the quality of life for patients is limited. In view of this, many companies and research institutes are actively devoted to the improvement of retinal implant microsystems. For example, a non-planar chipset is proposed in U.S. Patent Publication No. 9155881B2 filed by the applicant, which has a flexible structure formed by bending and deforming a planar shape. The flexible structure includes at least one layer of semiconductor material, and openings of a plurality of cut-out channels around a central portion of the flexible structure extend from a periphery of the flexible structure toward the central portion, and the plurality of cut-out channels are used for decreasing a displacement stress generated when the planar shape is bent and deformed into the flexible structure. Outside the flexible structure, the flexible structure is further joined to at least one fixing structure via a joining structure, so that the flexible structure maintains its bent state.
A retinal implant detects the intensity of light, and electrically detects the intensity of light with a high spatial resolution and stimulates healthy optic nerves, for example, bipolar cells in a retina. To avoid that a leakage current damages nerve tissue or causes a system damage, only a stimulation electrode of the retinal implant is exposed and in contact with the tissue, and the rest is hermetically sealed, not allowing a test point or an electrode to be exposed.
As a result, it is difficult to ensure that the manufactured retinal implant functions properly before transplantation. However, functional assurance is an essential element in reducing the risk and costs of retina transplantation.
In addition, there is also a need for a method for effectively reducing the impedance of an electrode to enhance a stimulation effect.